Gut bacteria may play a role in diabetesThank you for reading this post, don't forget to subscribe!
Summary: People with higher levels of the gut bacteria Coprococcus tend to have higher insulin sensitivity, while those with higher levels of Flavonifractor have lower levels of insulin sensitivity. Researchers say specific gut bacteria may play a significant role in the development of type 2 diabetes.
source: Cedars Sinai Medical Center
One type of bacteria found in the gut may contribute to the development of type 2 diabetes, while another may protect against the disease, according to early results of an ongoing prospective study led by researchers at Cedars-Sinai.
The study, published in a peer-reviewed journal Diabetesfound that people with higher levels of a bacteria called Coprococcus tended to have higher insulin sensitivity, while those whose microbiomes had higher levels of the bacterium Flavonifractor tended to have lower insulin sensitivity.
For years, researchers have tried to understand why people develop diabetes by studying the composition of the microbiome, which is a collection of microorganisms including fungi, bacteria and viruses that live in the digestive tract.
The microbiome is thought to be influenced by drugs and diet. Studies have also found that people who don’t process insulin properly have lower levels of a certain type of bacteria that produces a type of fatty acid called butyrate.
Mark Goodarzi, M.D., Ph.D., director of the Endocrine Genetics Laboratory at Cedars-Sinai, is leading an ongoing study that is tracking and monitoring people at risk for diabetes to find out whether those with lower levels of these bacteria develop the disease .
“The big question we’re hoping to answer is: Did the microbiome differences cause the diabetes or did the diabetes cause the microbiome differences?” said Goodarzi, who is the study’s senior author and principal investigator of the multicenter study, called the Microbiome and Insulin Longitudinal Evaluation Study (MILES).
MILES researchers have been collecting information from participating black and non-Hispanic white adults between the ages of 40 and 80 since 2018. An earlier cohort study from the MILES study found that cesarean delivery was associated with a higher risk of developing prediabetes and diabetes.
For the latest study to come out of this ongoing trial, researchers analyzed data from 352 people without known diabetes who were recruited from Wake Forest Baptist Health System in Winston-Salem, North Carolina.
Study participants were asked to attend three clinic visits and collect stool samples prior to the visits. The researchers analyzed the data collected at the first visit. They conducted genetic sequencing of the stool samples, for example, to study the microbiomes of the participants and specifically look for bacteria that earlier studies had found to be associated with insulin resistance.
Each participant also completed a dietary questionnaire and performed an oral glucose tolerance test, which was used to determine the ability to process glucose.
The researchers found that 28 people had oral glucose tolerance test results that met criteria for diabetes. They also found that 135 people had prediabetes, a condition in which a person’s blood sugar levels are higher than normal, but not high enough to meet the definition of diabetes.
The research team analyzed the links between 36 butyrate-producing bacteria found in stool samples and a person’s ability to maintain normal insulin levels. They controlled for factors that may also contribute to a person’s diabetes risk, such as age, sex, body mass index, and race. Coprococcus and related bacteria form a network of bacteria with a beneficial effect on insulin sensitivity.
Although a butyrate producer, Flavonifractor has been associated with insulin resistance; previous work by others has found higher levels of Flavonifractor in the stools of people with diabetes.
The researchers are continuing to study samples from patients who participated in this study to learn how insulin production and microbiome composition change over time. They also plan to study how diet can affect the bacterial balance of the microbiome.
However, Goodarzi emphasized that it is too early to know how people can change their microbiome to reduce their risk of diabetes.
“As far as the idea of taking probiotics, that would really be somewhat experimental,” said Goodarzi, who also holds the Eris M. Field Chair in Diabetes Research at Cedars-Sinai.
“We need more research to identify the specific bacteria we need to modulate to prevent or treat diabetes, but that’s coming, probably in the next five to 10 years.”
About this microbiome and diabetes research news
Original research: Free access.
“Butyrate-producing bacteria and insulin homeostasis: the Microbiome and Insulin Longitudinal Evaluation Study (MILES)” by Jinrui Cui et al. Diabetes
Butyrate-producing bacteria and insulin homeostasis: the Microbiome and Insulin Longitudinal Evaluation Study (MILES)
Gut microbiome studies have documented depletion of butyrate-producing taxa in type 2 diabetes. We analyzed associations between butyrate-producing taxa and detailed measures of insulin homeostasis, the dysfunction of which underlies diabetes in 224 non-Hispanic whites and 129 African Americans, all of whom completed an oral glucose tolerance test. The faecal microbiome was assessed by whole-metagenome shotgun sequencing with taxonomic profiling.
We examined associations between 36 butyrate-producing taxa (n = 7 genera and 29 species) and insulin sensitivity, insulin secretion, disposition index, insulin clearance, and prevalence of dysglycemia (prediabetes plus diabetes, 46% of the cohort), adjusting for age, sex, BMI, and race.
The genus Coprococcus was associated with higher insulin sensitivity (β = 0.14; P = 0.002) and disposition index (β = 0.12; P = 0.012) and a lower rate of dysglycemia (odds ratio [OR] 0.91; 95% CI 0.85–0.97; P = 0.0025).
In contrast, Flavonifractor was associated with lower insulin sensitivity (β = -0.13; P = 0.004) and disposition index (β = −0.11; P = 0.04) and a higher incidence of dysglycemia (OR 1.22; 95% CI 1.08–1.38; P = 0.0013). Species-level analyzes found 10 bacteria associated with favorable directions of action and two bacteria with unfavorable associations on insulin homeostasis and dysglycemia.
Although most analyzed butyrate producers appear to be metabolically beneficial, this is not the case for all such bacteria, suggesting that microbiome-targeted therapeutic measures to prevent or treat diabetes should target specific butyrate-producing taxa rather than all butyrate producers.
#Gut #bacteria #play #role #diabetes